Two problems possibly related, in my back bath i hear water running in what i believe to be shower valve?

Question

i replaced the moen valve but did not stop water running theres no leak but i have had recent trouble with my water heater , possible air in line if so how do i bleed air from heater. also second issue is hot water comes from my cold side for 5 seconds at same bath?

Answer 1

go to your water meter and watch it to see if it is constantly running. if it doesnt stop running while everything is turned off you have a leak somewhere

Answer 2

Any air that's left in the water heater should resolve itself after a few days.  If you keep getting air in the system from the water heater, that could be a sign that your water heater is about to fail.  I'd suggest getting that checked out.

Hot water from the cold side can be caused by several things.  If the climate where you live is hot and your supply pipes run through an uninsulated attic, that's perfectly normal.  But if that's not the case, then it sounds like water could be leaking from the hot side of the Moen valve to the cold side.  No water would leak to the outside, just enough from the hot supply pipe to the cold supply pipe to give you your five seconds of hot water.